Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G18/00—Polymeric products of isocyanates or isothiocyanates
  • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
  • C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
  • C08G18/40—High-molecular-weight compounds
  • C08G18/62—Polymers of compounds having carbon-to-carbon double bonds
  • C08G18/6204—Polymers of olefins
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G18/00—Polymeric products of isocyanates or isothiocyanates
  • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
  • C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
  • C08G18/40—High-molecular-weight compounds
  • C08G18/62—Polymers of compounds having carbon-to-carbon double bonds
  • C08G18/6216—Polymers of alpha-beta ethylenically unsaturated carboxylic acids or of derivatives thereof
  • C08G18/625—Polymers of alpha-beta ethylenically unsaturated carboxylic acids; hydrolyzed polymers of esters of these acids
  • C08G18/6254—Polymers of alpha-beta ethylenically unsaturated carboxylic acids and of esters of these acids containing hydroxy groups
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D175/00—Coating compositions based on polyureas or polyurethanes; Coating compositions based on derivatives of such polymers
  • C09D175/04—Polyurethanes
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/31504—Composite [nonstructural laminate]
  • Y10T428/31551—Of polyamidoester [polyurethane, polyisocyanate, polycarbamate, etc.]

Definitions

• the present invention provides coating agents based on hydroxyl-functional (meth)acrylic copolymers and polyisocyanates, that can be processed to weather-resistant coatings that are distinguished by rapid drying, high brilliance, security against sag, and weathering resistance.
• the object of the invention was the provision of coating agents that are suitable in particular for top coatings (pigmented top coatings or transparent top coatings), provide short drying times, trouble-free application even when lacquering in only one spraying operation (that are sagproof and hotplate-safe) and lead to coatings that are free from yellowing and weather-resistant and produce high gloss, body and brilliance.
• coating agents that form one subject of the invention.
• These coating agents are based on hydroxy-functional (meth)acrylic copolymers, aliphatic and/or cycloaliphatic polyisocyanates, solvents, and optionally customary lacquer additives and pigments. They are characterised in that they are free from epoxy resins and nitrocellulose and contain as binder
• component B an aliphatic add/or cycloaliphatic polyisocyanate or a mixture of such polyisocyanates in such an amount that 0.5 to 2.0 isocyanate groups are present for one hydroxyl group of component A).
• a (meth)acrylic copolymer is used as component A), wherein
• component a1) is styrene or a styrene derivative
• component a2) is a hydroxyethyl methacrylate
• component a3) is n-butyl methacrylate.
• component A) is obtainable from:
• (meth)acrylic used here is intended to mean acrylic and/or methacrylic.
• the (meth)acrylic copolymers included in the coating agent according to the invention may be manufactured by polymerization according to customary processes, e.g. bulk, solution or bead polymerization.
• customary processes e.g. bulk, solution or bead polymerization.
• the various polymerization processes are well known and described in: Houben-Weyl, Methoden der Organischen Chemie, 4. Aufl., Band 14/1, pp 24-255 (1961).
• the solution polymerization process is preferred for the manufacture of the (meth)acrylic-copolymers used in the coating agent according to the invention.
• the solvent is charged to the reaction vessel and heated to the boiling point and the monomers/initiator mixture is charged in a certain time.
• the polymerization is preferably carried out at temperatures between 100° C. and 160° C., preferably between 130° C. and 150° C.
• the polymerization reaction can be started with known polymerization initiators.
• Suitable initiators are for example per- and azo-compounds, which decompose thermally into radicals in a first-order reaction.
• the type and amount of the initiator are so chosen that at the polymerization temperature during the inflow phase, a radical supply exists that is as nearly constant as possible.
• initiators for the polymerization examples include: dialkyl peroxides, such as di-tert-butyl peroxide and dicumyl peroxide; diacyl peroxides, such as dibenzoyl peroxide and dilauroyl peroxide; hydroperoxides, such as cumene hydroperoxide and tert-butyl hydroperoxide; peresters, such as tert-butyl perbenzoate, tert-butyl perpivalate, tert-butyl-per-3,5,5-trimethylhexanoate and tert-butyl-per-2-ethylhexanoate; peroxydicarbonates, such as di-2-ethylhexyl peroxydicarbonate and dicyclohexyl peroxydicarbonate; perketals, such as 1,1-bis(tert-butylperoxy)-3,5,5-trimethylcyclohexane and 1,1-bis
• the polymerization initiators in particular the peresters, are preferably used in an amount of 0.2 to 5 wt % of the weight of monomers.
• glycol ethers such as ethylene glycol dimethyl ether
• glycol ether esters such as ethyl glycol acetate, butyl glycol acetate, 3-methoxy-n-butyl acetate, butyldiglycol acetate and methoxypropyl acetate
• esters such as butyl acetate, isobutyl acetate and amyl acetate
• ketones such as methyl ethyl ketone, methyl isobutyl ketone, diisobutyl ketone, cyclohexanone and isophorone
• aromatic hydrocarbons such as xylene and Solvesso 100 (registered trade mark)
• aliphatic hydrocarbons can likewise be used, blended with the aforementioned solvents.
• Chain-transfer agents can be co-utilized, especially in the preferred solution polymerization, for control of the molecular weight.
• Examples are mercaptans, thioglycolic acid esters, chlorohydrocarbons, cumene and dimeric ⁇ -methylstyrene
• the polymerization conditions (reaction temperature, inflow time of the monomer mixture, solution concentration) are so arranged that the (meth)acrylic copolymers for the coating agent according to the invention have a number-average molecular weight (determined by gel permeation chromatography using polystyrene as standard) of between 10,000 and 20,000.
• the (meth)acrylic copolymers containing hydroxyl groups of the coating agent according to the invention fall in a glass transition temperature range of +40° C. to +60° C., calculated from the glass transition temperatures of the homopolymers of the individual monomers quoted in the literature (Fox equation, see e.g. Polymeric Materials, Batzer, 1935, page 307).
• Compounds used as monomer components for the production of the (meth)acrylic copolymers containing hydroxyl groups according to the invention are aromatic vinyl compounds, preferably styrene and its derivatives, such as vinyltoluene, hydroxyalkyl methacrylates, especially with 2 to 4 C atoms in the alkyl component, preferably 2hydroxyethyl methacrylate, alkyl (meth)acrylates, especially with 2 to 6 C atoms in the alkyl component, preferably n-butyl acrylate, and (meth)acrylic acid, preferably acrylic acid.
• aromatic vinyl compounds preferably styrene and its derivatives, such as vinyltoluene, hydroxyalkyl methacrylates, especially with 2 to 4 C atoms in the alkyl component, preferably 2hydroxyethyl methacrylate, alkyl (meth)acrylates, especially with 2 to 6 C atoms in the alkyl component, preferably n-butyl acrylate
• the (meth)acrylic copolymers are combined in the coating agents according to the invention with cross-linking agents, namely polyisocyanates or prepolyisocyanates.
• polyisocyanate cross-linkers The proportion of polyisocyanate cross-linkers is so chosen that 0.5 to 2.0 isocyanate groups are present for one hydroxyl group of the binder component. Excess isocyanate groups can be removed by reaction with moisture and contribute to the cross-linking. Aliphatic and/or cycloaliphatic polyisocyanates can be used, such as hexamethylene diisocyanate, trimethylhexamethylene diisocyanate and isophorone diisocyanate.
• polyisocyanates examples include a reaction product containing biuret groups from 3 moles of hexamethylene diisocyanate with 1 mole of water, with an NCO content of ca. 22% (corresponding to the commercial product Desmodur N® of BAYER AG); a polyisocyanate containing isocyanurate groups that is manufactured by trimerization of 3 moles of hexamethylene diisocyanate with an NCO content of about 21.5% (corresponding to the commercial product Desmodur N 3390® of BAYER AG); or polyisocyanate containing urethane groups, which are reaction products from 3 moles of tolylene diisocyanate and 1 mole of trimethylolpropane with an NCO content of about 17.5% (corresponding to the commercial product Desmodur L® of BAYER AG). Desmodur N® and Desmodur N 3390® preferably are used.
• the coating agents for transparent or pigmented top coatings that contain the (meth)acrylic copolymers to be used according to the invention can contain, in addition to solvents, as for example the solvents already mentioned for the manufacture by solution polymerization, auxiliary substances customary in paints, such as for example light stabilizers, levelling agents based on (meth)acrylic homopolymers, silicone oils, plasticizers such as esters of phosphoric acid, phthalic acid or citric acid; thixotroping agents, pyrogenic silica, hydrogenated castor oil; curing accelerators for the reaction of the (meth)acrylic copolymers according to the invention with polyisocyanate resins, e.g.
• organic metal salts such as dibutyltin dilaurate and zinc naphthenate; and furthermore compounds containing tertiary amino groups, such as triethylamine and dimethylaminoethanol.
• customary organic or inorganic lacquer pigments are suitable as pigments.
• a proportion of high-solid resins which optionally contain reactive diluents, can be co-utilized in the coating agents according to the invention without loss of properties.
• the coating agents according to the invention are particularly suitable for the production of coatings which have very short drying times of, e.g. 15 to 20 minutes at low temperatures of e.g. 20° to 80° C., preferably up to 60° C.
• the obtained coatings are not sticking even if they are still warm after drying.
• the obtained products can immediately assembled.
• the coating agents of the invention can provide thick layers of about 35 to 120 ⁇ m without problems.
• the application of such thick layers can be achieved even in only one single spraying operation.
• layers of up to 60 ⁇ m and not less than 50 ⁇ m are preferred.
• the mentioned thickness refers to the dry film thickness.
• Such thick layers can be achieved without sagging, without blisters and without any troubles even when lacquering in only one spraying operation. Overspray is absorbed during the spraying operation by the obtained coating without causing any troubles. This is very surprising since the coatings are very fast drying. Therefore, it is possible to use the coating agents of the present invention for total lacquering of substrates such as motorvehicle bodies and their parts.
• the coating agents of the invention are particularly suitable for the repair lacquering of motorvehicle bodies and their parts.
• the coating agents of the present invention for the production of pigmented or transparent top coating of an air-drying of forced-drying multilayer coating.
• a transparent top coating can be applied for example by the wet-on-wet process to conventional or aqueous base coats, where upon both coats are cured together for e.g. 15 to 20 minutes at e.g. 50° to 80° C.
• the invention therefore also relates to processes for the production of multilayer coatings or the use of the coating agents for the production of multilayer coatings wherein in particular the top coat and/or clear coat layers of multilayer coatings are produced by the coating agents according to the invention.
• Viscosity (mPa.s at 25° C.) 1235 1850 2380
• the following hardener was prepared as second component (component B) of the coating agent:
• the above prepared coating agents or clear coats containing binder A or binders according to the comparative tests 1 and 2 were each mixed shortly before processing in the volume ratio of 50.0% (binder A), 47.2% (comparative test 1) and 46.5% (comparative test 2) with the above hardener (component B) of the coating agent.
• the slight divergences of the mixing ratio are necessary for the 100% cross-linking.
• the chemically curing coatings obtained were applied by spray application in a dry film thickness of 50 ⁇ m to 60 ⁇ m by the wet-on-wet process to a layer of base coat and, after a flashing-off phase of 5 minutes, then cured for 20° minutes at 60° C.
• the results of the lacquer-technology investigations are shown in the following table.
• the following pigmented formulations were produced by customary dispersion processes, using ordinary commercial, wetting, dispersing, and antisettling agents.
• each coating agent was mixed in the volume ratio of 50.0% with the hardener (component B) of the coating agent.
• the chemically curing coatings obtained were applied by spraying at a dry film thickness of 50 ⁇ m to 60 ⁇ m by the wet-on-wet process to a base coat layer and, after a flashing-off phase of 5-10 minutes, then cured for 20 minutes at 60° C.
• the results of the lacquer technology investigations are shown in the following table.

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Health & Medical Sciences (AREA)
• Polymers & Plastics (AREA)
• Medicinal Chemistry (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Wood Science & Technology (AREA)
• Life Sciences & Earth Sciences (AREA)
• Materials Engineering (AREA)
• Engineering & Computer Science (AREA)
• Paints Or Removers (AREA)
• Pigments, Carbon Blacks, Or Wood Stains (AREA)
• Application Of Or Painting With Fluid Materials (AREA)
• Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)
• Manufacture Of Motors, Generators (AREA)
• Polyurethanes Or Polyureas (AREA)

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• 1993
  • 1993-06-23 DE DE4320727A patent/DE4320727A1/de not_active Withdrawn
• 1994
  • 1994-06-17 CA CA 2126112 patent/CA2126112A1/en not_active Abandoned
  • 1994-06-21 DK DK94109545T patent/DK0630923T4/da active
  • 1994-06-21 AT AT94109545T patent/ATE175690T1/de not_active IP Right Cessation
  • 1994-06-21 ES ES94109545T patent/ES2127851T5/es not_active Expired - Lifetime
  • 1994-06-21 EP EP94109545A patent/EP0630923B2/de not_active Expired - Lifetime
  • 1994-06-21 DE DE59407624T patent/DE59407624D1/de not_active Expired - Fee Related
  • 1994-06-22 JP JP14023694A patent/JPH0753917A/ja active Pending
• 1996
  • 1996-09-24 US US08/718,729 patent/US5731382A/en not_active Expired - Fee Related
• 1999
  • 1999-02-03 GR GR990400381T patent/GR3029301T3/el unknown

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